Ionic surfactants ionize in an aqueous medium and can unite oil- or water soluble properties of a molecule and reduce water surface tension.

Ionic surfactants ionize in an aqueous medium and can unite oil- or water soluble properties of a molecule and reduce water surface tension.

• A. Do not ionize in water
• B. Ionize in an aqueous medium and can unite oil or water soluble properties and reduce water surface tension
• C. Are always hazardous
• D. Cannot mix with herbicides

Answer: (B)

Ionic surfactants are surface-active compounds that split into ions when placed in water. Their molecules have both a hydrophilic (water-loving) head and a hydrophobic (oil-loving) tail, which lets them bridge oil and water and orient themselves at interfaces. This amphiphilic structure is what lets them reduce the surface tension of water: at the air–water interface, their heads stay in the water while the tails extend away, lowering the energy required to create new surface. That combination—ionizing in aqueous solution, having both oil- and water-soluble character due to their molecular structure, and reducing water’s surface tension—is exactly what makes ionic surfactants effective. They can also form micelles at higher concentrations to solubilize oily substances, aiding mixing of oil and water and improving the delivery of additives like herbicides. The other statements aren’t generally true: some surfactants can ionize in water, so saying they do not is inaccurate; not all surfactants are hazardous, so “always hazardous” isn’t correct; and surfactants are commonly used with herbicides to improve effectiveness, so “cannot mix with herbicides” isn’t correct.

Ionic surfactants are surface-active compounds that split into ions when placed in water. Their molecules have both a hydrophilic (water-loving) head and a hydrophobic (oil-loving) tail, which lets them bridge oil and water and orient themselves at interfaces. This amphiphilic structure is what lets them reduce the surface tension of water: at the air–water interface, their heads stay in the water while the tails extend away, lowering the energy required to create new surface.

That combination—ionizing in aqueous solution, having both oil- and water-soluble character due to their molecular structure, and reducing water’s surface tension—is exactly what makes ionic surfactants effective. They can also form micelles at higher concentrations to solubilize oily substances, aiding mixing of oil and water and improving the delivery of additives like herbicides.

The other statements aren’t generally true: some surfactants can ionize in water, so saying they do not is inaccurate; not all surfactants are hazardous, so “always hazardous” isn’t correct; and surfactants are commonly used with herbicides to improve effectiveness, so “cannot mix with herbicides” isn’t correct.